using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.PMR.Common;
using Google.Protobuf;
using System.IO;

namespace Tango.PMR
{
    /// <summary>
    /// Represents composition of message <see cref="MessageContainer"/> and a PMR message. aka Tango message.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class TangoMessage<T> : ITangoMessage where T : IMessage<T>
    {
        /// <summary>
        /// Gets the container that will encapsulate the actual PMR message.
        /// </summary>
        public MessageContainer Container { get; set; }

        /// <summary>
        /// Gets or sets the message.
        /// </summary>
        public T Message { get; set; }

        /// <summary>
        /// Gets or sets the PMR message type.
        /// </summary>
        public MessageType Type { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="TangoMessage{T}"/> class.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <param name="type">The type.</param>
        public TangoMessage(T message, MessageType type)
        {
            Message = message;
            Type = type;

            Container = new MessageContainer();
            Container.Token = Guid.NewGuid().ToString();
            Container.Type = Type;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="TangoMessage{T}"/> class.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <param name="type">The type.</param>
        public TangoMessage(MessageContainer container, T message)
        {
            Message = message;
            Container = container;
            Type = container.Type;
        }

        /// <summary>
        /// Serializes the Tango message to byte array.
        /// </summary>
        /// <returns></returns>
        public byte[] ToBytes()
        {
            using (MemoryStream ms = new MemoryStream())
            {
                Message.WriteTo(ms);
                ms.Position = 0;
                Container.Data = ByteString.FromStream(ms);
            }

            using (MemoryStream ms = new MemoryStream())
            {
                Container.WriteTo(ms);
                return ms.ToArray();
            }
        }

        /// <summary>
        /// Serializes the Tango message to byte array representing a serialized JSON object of this Tango message.
        /// </summary>
        /// <returns></returns>
        public byte[] ToJsonBytes()
        {
            Container.Data = Message.ToByteString();
            return Encoding.UTF8.GetBytes(Container.ToString());
        }

        /// <summary>
        /// Performs an implicit conversion from <see cref="T"/> to <see cref="TangoMessage{T}"/>.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns>
        /// The result of the conversion.
        /// </returns>
        public static implicit operator TangoMessage<T>(T message)
        {
            var tangoMessage = MessageFactory.CreateTangoMessage<T>();
            tangoMessage.Message = message;
            return tangoMessage;
        }

        /// <summary>
        /// Performs an implicit conversion from <see cref="TangoMessage{T}"/> to <see cref="T"/>.
        /// </summary>
        /// <param name="instance">The instance.</param>
        /// <returns>
        /// The result of the conversion.
        /// </returns>
        public static implicit operator T(TangoMessage<T> instance)
        {
            return instance.Message;
        }

        /// <summary>
        /// Performs an implicit conversion from <see cref="System.Byte[]"/> to <see cref="TangoMessage{T}"/>.
        /// </summary>
        /// <param name="data">The data.</param>
        /// <returns>
        /// The result of the conversion.
        /// </returns>
        public static implicit operator TangoMessage<T>(byte[] data)
        {
            return MessageFactory.ParseTangoMessage<T>(data);
        }

        /// <summary>
        /// Returns a <see cref="System.String" /> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String" /> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return String.Format(@"Message Type: {0}
Token: {1}
Error: {2}
Message: {3}", Container.Type, Container.Token, Container.Error, Message.ToString());
        }
    }
}